Cook over medium - low heat, stirring constantly and adding
more pasta cooking liquid if needed, until butter has melted and a thick, glossy sauce has formed, about 2 minutes.
Take
reserved pasta cooking liquid and add slowly to pot in 1/4 cup increments, stirring to break down cheese until mixture becomes smooth and creamy.
Drain, reserving 1 cup of
the pasta cooking liquid.
Add pasta and
pasta cooking liquid; simmer until sauce thickens, 2 — 5 minutes.
Add pasta, tossing and adding more
pasta cooking liquid as needed, until coated.
Add pasta and reserved
pasta cooking liquid to skillet and cook, tossing to coat, until liquid has reduced to a creamy sauce, about 4 minutes.
Drizzle with more olive oil and add some of
the pasta cooking liquid if it seems dry.
Immediately add 1/2 cup
pasta cooking liquid to keep garlic from burning; reduce heat to low and gradually add butter, swirling skillet and adding more pasta cooking liquid as needed, until a thick, glossy sauce forms.
Add pasta and 1 cup reserved
pasta cooking liquid to skillet and cook, tossing to coat, until sauce has reduced, 3 — 4 minutes.
salt, 1/4 cup
pasta cooking liquid, and remaining 3/4 cup Parmesan and 1/2 tsp.
Strain the pasta, reserving 1/2 cup of
the pasta cooking liquid.
Drain pasta, reserving 1 cup
pasta cooking liquid; return pasta to pot.
Cook over medium heat, stirring and adding remaining 1/4 cup
pasta cooking liquid to loosen if needed, until sauce is thickened and emulsified, about 2 minutes.
Add pasta, remaining 1/4 cup oil, and 3/4 cup
pasta cooking liquid to pan.
Drain, reserving 1/2 cup
pasta cooking liquid, and run under cold water to stop the cooking.
Add mozzarella, provolone, cheddar, Parmesan, cream, and reserved 1/2 cup
pasta cooking liquid and mix to combine.
Using tongs, transfer pasta to pot with mushrooms and add 1 cup
pasta cooking liquid.
Add 3/4 cup
pasta cooking liquid to reserved skillet and bring to a gentle boil over medium heat, swirling often to encourage drippings and liquid to emulsify, about 1 minute.
Meanwhile, cook pasta in a large pot of boiling lightly salted water, stirring occasionally, until pasta is about halfway cooked (not quite al dente); drain, reserving 1 1/2 cups
pasta cooking liquid.
Stir in crème fraîche, 1/2 cup
pasta cooking liquid, and remaining 1 tsp.
Add pasta to pot with sauce along with butter and 1 cup
pasta cooking liquid.
Add zucchini, spaghetti,
pasta cooking liquid, 1/4 cup oil, and remaining 1/2 cup basil leaves and toss to combine; season with salt and pepper.
Drain, reserving 1 1/2 cups
pasta cooking liquid.
pasta cooking liquid, then gradually add cheese, tossing until melted and emulsified.